From Gentoo Wiki
Gentoo Releases should conform to open standards where possible and document the cases where they are not.
- Filesystem Hierarchy Standard (FHS)
- Linux Standard Base (LSB)
- Single UNIX Specification (SUS)
- Portable Operating System Interface (POSIX)
"The Open Group supports the community at large by making many of its test tools freely available..."
Unix Standard Utilities
ln -s $(which busybox) /usr/local/bin/vi
eselect editor set /usr/local/bin/vi